1. Field of the Invention
This invention relates generally to a high-voltage stabilizing circuit suitable for use in stabilizing a high-voltage that is supplied to a cathode ray tube from a flyback transformer and, particularly, a high-voltage stabilizer for use with a flat-type cathode ray tube.
2. Description of the Prior Art
It is known to utilize the horizontal output transformer as the "flyback" transformer to develop the high-voltage necessary for a cathode ray tube. This output transformer typically provides both the high-voltage for the cathode ray tube and also the horizontal scanning voltage. In such output or flyback transformer high-voltage circuits, it is known that the high-voltage output fluctuates depending upon the total load in the transformer secondary, which is a function of the resistance of the transformer winding, the impedances of the rectifier diode and bypass capacitor, and other circuit elements forming the switching circuit. Additionally, the high-voltage output will also be influenced by the cathode current of the cathode ray tube, which varies in response to the input video signal, because the video output circuit that receives the video signal is powered by a low voltge also produced by the flyback transformer. The resultant effect of these high-voltage fluctuations is that the position and size of the picture formed on the cathode ray tube will vary. While such picture variations are known, they have not been critical, because the variations in position and size of the picture are not necessarily noticeable in a conventional cathode ray tube. This is because the axial alignment of the guns relative to the phosphorus screen do not cause a large shift in the picture for normal variations in the high-voltage output. However, such position and size variations of the picture are quite conspicuous in a so-called flat-type cathode ray tube, such as is employed in currently available miniature, personal television receivers. This conspicuous variation in size and position of the picture in such flat-type cathode ray tubes is due to the relatively small angle between the phosphorus screen and the center axis of the electron gun or guns of the tube, relative to a conventional cathode ray tube.